I sanded down the seal gutter on the left door first with the oscillationg sander and then by hand. I prepped both doors for gapping by sanding and cleaning the areas that will get covered with slurry. I then applied an 1/8" weather stripping around the right door in order to establish a proper gap. I also applied some vinyl tape to the outside of the weather stripping to help with door removal once the slurry has dried.